fix(python): classify historical headers and signed flags

Fixes #6568, #6487

src/domain/python/pythonPyc.test.ts

@@ -9,18 +9,30 @@ it("maps pinned CPython 3.7–3.13 magics and leaves gaps unknown", () => {
   expect(pythonPycMagicEntry(3394)).toEqual({
     python_version: "3.7",
     code_layout: "py37",
+    header_bytes: 16,
+  });
+  expect(pythonPycMagicEntry(3390)).toMatchObject({
+    python_version: "3.7",
+    header_bytes: 12,
+  });
+  expect(pythonPycMagicEntry(3391)).toMatchObject({
+    python_version: "3.7",
+    header_bytes: 12,
   });
   expect(pythonPycMagicEntry(3413)).toEqual({
     python_version: "3.8",
     code_layout: "py38",
+    header_bytes: 16,
   });
   expect(pythonPycMagicEntry(3531)).toEqual({
     python_version: "3.12",
     code_layout: "py311",
+    header_bytes: 16,
   });
   expect(pythonPycMagicEntry(3571)).toEqual({
     python_version: "3.13",
     code_layout: "py311",
+    header_bytes: 16,
   });
   expect(pythonPycMagicEntry(3450)).toBeNull();
   expect(pythonPycMagicEntry(62171)).toBeNull();

src/domain/python/pythonPyc.ts

@@ -9,8 +9,8 @@ export const PYTHON_PYC_CHECK_SOURCE = 0x2;
 const uint = z.number().int().min(0).max(0xffffffff);
 const index = z.number().int().nonnegative();
 const signedInt32 = z.number().int().min(-0x80000000).max(0x7fffffff);
-/** Non-negative CPython `int` counts. `0xffffffff` is -1 and is not evidence. */
-const signedCount = z.number().int().min(0).max(0x7fffffff);
+/** Non-negative CPython `int` counts. */
+const nonNegativeInt32 = z.number().int().min(0).max(0x7fffffff);
 
 /** Marshal TYPE_CODE field order for CPython 3.7, 3.8–3.10, and 3.11+. */
 export const PYTHON_PYC_CODE_LAYOUTS = ["py37", "py38", "py311"] as const;
@@ -19,14 +19,16 @@ export type PythonPycCodeLayout = (typeof PYTHON_PYC_CODE_LAYOUTS)[number];
 type MagicEntry = {
   readonly python_version: string;
   readonly code_layout: PythonPycCodeLayout;
+  readonly header_bytes: 12 | 16;
 };
 
 const magics = (
   values: readonly number[],
   python_version: string,
   code_layout: PythonPycCodeLayout,
+  header_bytes: 12 | 16 = PYTHON_PYC_HEADER_BYTES,
 ): ReadonlyArray<readonly [number, MagicEntry]> =>
-  values.map((magic) => [magic, { python_version, code_layout }]);
+  values.map((magic) => [magic, { python_version, code_layout, header_bytes }]);
 
 const consecutive = (
   start: number,
@@ -46,7 +48,8 @@ const consecutive = (
  * bytecode opcode tables.
  */
 export const PYTHON_PYC_MAGIC_TABLE: ReadonlyMap<number, MagicEntry> = new Map([
-  ...magics([3390, 3391, 3392, 3393, 3394], "3.7", "py37"),
+  ...magics([3390, 3391], "3.7", "py37", 12),
+  ...magics([3392, 3393, 3394], "3.7", "py37"),
   ...magics([3400, 3401], "3.8", "py37"),
   ...magics([3410, 3411, 3412, 3413], "3.8", "py38"),
   ...magics([3420, 3421, 3422, 3423, 3424, 3425], "3.9", "py38"),
@@ -159,12 +162,12 @@ const pythonCodeFields = {
   qualname: z.string().nullable(),
   filename: z.string(),
   firstlineno: signedInt32,
-  argcount: signedCount,
-  posonlyargcount: signedCount.nullable(),
-  kwonlyargcount: signedCount,
-  nlocals: signedCount.nullable(),
-  stacksize: signedCount,
-  flags: uint,
+  argcount: nonNegativeInt32,
+  posonlyargcount: nonNegativeInt32.nullable(),
+  kwonlyargcount: nonNegativeInt32,
+  nlocals: nonNegativeInt32.nullable(),
+  stacksize: nonNegativeInt32,
+  flags: signedInt32,
   names: z.array(z.string()),
   varnames: z.array(z.string()).nullable(),
   freevars: z.array(z.string()).nullable(),